410 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(except Amoeba) in appreciable numbers at the bottom is most often 

 coincident with or immediately to its surface minimum, and portends its 

 more or less rapid elimination as an important factor in the life of the 

 infusion. Numerous abnormal individuals and cysts are frequently to 

 be found at the bottom immediately after the surface maximum. There 

 is some evidence that Amoebae migrate from the surface to the bottom, 

 which is their chief abode. 



The observations give the impression that some Amoebae appear as 

 amoebae-flagellates which gradually increase in size and finally assume 

 the form of typical A. proteus. There is some evidence that the relative 

 potential of division of the various forms may have an appreciable in- 

 fluence on the sequence of the maxima. Emphasis is laid on the strictly 

 biological inter-relations (e.g. those involving food and specific excretion 

 products) of the various forms as the most important determining factors 

 in the observed sequence. The observations suggest that conjugation 

 will be found to be a means resorted to by many species to survive acute 

 changes in the environment, which, for example, preclude eucystment. 



The author has much more that is of great interest to communicate 

 in regard to his study of the kaleidoscopic series of phenomena which a 

 hay infusion presents, from the time of its inception until it finally 

 reaches a stage of sterility, or, in the presence of sunlight, of practically 

 stable equilibrium in which animals and green plants become so adjusted 

 that a veritable microcosm is established. 



Chilodon parasitic on Goldfish.*—- E. Andre describes the infesta- 

 tion of goldfish at Geneva with legions of Chilodon cyprini Moroff, 

 which proved rapidly fatal. Carp and Eupomofis in the same aquarium 

 were not affected, so it looks as if the goldfishes had been already in 

 some way enfeebled. The Infusorians were free in the mucus of the 

 skin and gills ; they produce asphyxiation. It is possible that their 

 excretory products are poisonous. The author calls attention to the 

 variability in form and cih'ation, and maintains that Chilodon hexastichus 

 Kiernik should be merged in C. ryprini Moroff. 



Life-cycle of Spirochseta gallinarum.t — E. Hindle sums this up as 

 follows. Commencing with the ordinary parasite in the blood of the 

 fowl, the spirochfete grows until it reaches a certain length (16-19 /x.) 

 and then divides by a peculiar mode of transverse division. This pro- 

 cess is repeated, and is probaljly the only method of multiplication of 

 the parasite within the blood. When the spirochsetes disappear from the 

 circulation, some of them break up into coccoid bodies, which, however, 

 do not usually develop in the fowl. 



When the spirochetes are ingested by Argas persicus, some of them 

 pass through the gut-wall into the coelomic fluid. From this medium 

 they bore their way into the cells of the various organs of the tick, and 

 there break up into a number of coccoid bodies. These intracellular 

 forms multiply by ordinary fission in the cells of the Malpighian tubules 

 and gonads. Some of the coccoid l)odies are formed in the lumen of 

 the gut and IMalpighian tubules. The result is that some of the 



* Rev. Suisse Zool., xx. (1912) pp. 207-12 (1 fig.), 

 t Parasitology, iv. (1912) pp. 463-77 (6 figs.). 



